Renal failure is a disease state in which renal functions are damaged severely such that internal environment of the living body can no longer be maintained in normal conditions. In particular, acute renal failure involves a sudden loss of the kidneys' ability to excrete wastes, concentrate urine, and conserve electrolytes. Causes of acute renal failure include acute tubular necrosis (ATN), myoglobinuria (myoglobin in the urine), infections such as acute pyelonephritis or septicemia, urinary tract obstruction such as a narrowing of the urinary tract (stricture), tumor, kidney stones, nephrocalcinosis, enlarged prostate with subsequent acute bilateral obstructive uropath, severe acute nephritic syndrome, disorders of the blood, malignant hypertension, and autoimmune disorders such as scleroderma. Other causes such as poisons and trauma, for example a direct and forceful blow to the kidneys, can also lead to renal failure.
Chronic renal failure is a gradual loss of kidney functions and usually occurs over a number of years as the internal structures of the kidney are slowly destroyed. Causative diseases include glomerulonephritis of any type, polycystic kidney disease, diabetes mellitus, hypertension, Alport syndrome, reflux nephropathy, obstructive uropathy, kidney stones and infection, and analgesic nephropathy. Chronic renal failure results in the accumulation of fluid and waste products in the body, causing azotemia and uremia.
Therapeutic agents for acute renal failure include loop diuretics and osmotic diuretics, which are used in expectation of recovery of renal functions by increasing the flow in kidney tubules so as to wash away casts formed in the tubules and thereby prevent obstruction of the tubules. Agents for chronic renal failure include imidazole angiotensin-II (AII) receptor antagonists and anipamil. However, depending on the manner of use, these agents present the risk of inviting hearing disorders and the even more severe adverse side effects of heart failure and pulmonary edema.